Buildhub UnderpinCrete Underpinning Cement 50kg

The Buildhub UnderpinCrete Controlled Low-Strength Material (CLSM) is a flowable, self-levelling cementitious fill material designed for applications where a combination of flowable placement, moderate structural support, and future re-excavatability is required. Unlike standard high-strength structural concrete, which becomes impractical to excavate once cured, UnderpinCrete is proportioned to achieve a 28-day compressive strength in the range of 0.5 to 1.0 MPa — strong enough to provide permanent sub-base support and prevent settlement, but excavatable with standard mechanical equipment if future service access is required.

Underpinning is the primary application for which UnderpinCrete is named — the progressive installation of new foundation support beneath an existing structure, where the access-constrained geometry of underpinning bays typically requires a flowable material that can be placed without vibration compaction from restricted openings. UnderpinCrete flows under gravity to fill the entire bay volume including areas beneath existing footings that mechanical compaction could never reach, providing uniform support to the existing structure that prevents differential settlement between underpinned bays.

Beyond underpinning, UnderpinCrete is extensively used for highway and utility trench reinstatement where flow-fill backfill eliminates the differential settlement that mechanical compaction in confined trenches cannot reliably prevent, reducing the pothole-generation maintenance burden associated with traditional granular trench backfill. The flowable nature of UnderpinCrete allows complete filling of irregular trench geometries including those containing service pipes and ducts without void formation.

UnderpinCrete is designed to be mixed at site by adding to a standard drum mixer or ready-mix lorry at the specified water-to-powder ratio. Pumped application is possible with appropriate equipment. Buildhub provides site trial mix guidance for specific required strength targets.